Solar Array, Arrangement with a Plurality of Solar Arrays and Use of the Solar Array or the Arrangement

ABSTRACT

A solar array is provided with a first heat-transfer fluid transporting line (parabolic trough loop) for transporting a first heat transfer fluid, and at least one further heat-transfer fluid transporting line for transporting a further heat transfer fluid arranged to receive solar energy from, for example, a parabolic-trough solar array. The first heat-transfer fluid transporting line and the further heat-transfer fluid transporting line are coupled to form an overall heat-transfer fluid transporting line (for example, as a parabolic trough loop). The first heat-transfer fluid transporting line is connected to at least one main line pump for pumping the first heat transfer fluid through the heat-transfer-fluid transporting line and the further heat-transfer fluid transporting line is connected to at least one further main line pump for pumping the further heat transfer fluid through the further heat-transfer-fluid transporting line. The first and further heat-transfer fluids may be the same fluid.

This application is a National Stage of PCT International Application No. PCT/EP2012/061764 , filed Jun. 20, 2012, which claims priority under 35 U.S.C. §119 from German Patent Application No. 10 2011 078 474.8, filed Jun. 30, 2011, the entire disclosures of which are herein expressly incorporated by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a solar array and an arrangement with a plurality of solar arrays. Use of the solar array or the arrangement is furthermore described.

The solar array is, for example, a parabolic-trough solar array. Such a parabolic-trough solar array has multiple parabolic-trough loops. These parabolic-trough loops have heat-transfer fluid transport lines (heat-transfer fluid transport pipes) through which a heat-transfer fluid (heat-transfer medium), for example a thermal oil, is pumped.

In a parabolic-trough solar array, parabolic-trough mirrors serve as a solar energy collector unit. Here, solar energy is fed, via a parabolic-trough mirror, into the heat-transfer fluid which is situated in the heat-transfer fluid transport line. For this purpose, the heat-transfer fluid transport line is arranged in a focus line of the parabolic-trough mirror. Moreover, the heat-transfer fluid transport line is configured in the region of the parabolic-trough mirror as a so-called receiver tube. This means that the surface of the line is configured in such a way that as much sunlight as possible can be absorbed.

The parabolic-trough solar arrays of a parabolic-trough power plant or the parabolic-trough loops of a parabolic-trough solar array are usually operated with the aid of a central main pump for pumping the heat-transfer fluid through the parabolic-trough loops. The distribution of the heat-transfer fluid over the individual parabolic-trough loops is here controlled with the aid of control valves.

The central main pump is as a rule designed specifically for the respective solar array, i.e. the central main pumps are custom-made parts and hence expensive.

The object of the present invention is to provide a more cost-effective option than in the prior art for conveying the heat-transfer fluid through the parabolic-trough loops of a solar array.

The object is achieved by a solar array with a heat-transfer fluid transport line for transporting a heat-transfer fluid, and at least one further heat-transfer fluid transport line for transporting a further heat-transfer fluid, wherein the heat-transfer fluid transport line and the further heat-transfer fluid transport line are coupled together to form a combined heat-transfer fluid transport line, the heat-transfer fluid transport line is connected to at least one line main pump for pumping the heat-transfer fluid through the heat-transfer fluid transport line, and the further heat-transfer fluid transport line is connected to at least one further line main pump for pumping the further heat-transfer fluid through the further heat-transfer fluid transport line.

Each of the heat-transfer fluid transport lines is preferably connected in each case to at least one solar energy collector unit for feeding solar energy into the heat-transfer fluid arranged in the respective heat-transfer fluid transport line. The solar energy collector unit thus in particular has at least one parabolic-trough mirror.

The solar array has at least two loops (heat-transfer fluid transport lines). The two heat-transfer fluid transport lines preferably form a closed circuit (combined heat-transfer fluid transport line) for a single heat-transfer fluid. In other words, the further heat-transfer fluid is none other than the heat-transfer fluid. The heat-transfer fluid is, for example, a thermal oil. Alternatively, the heat-transfer fluid can also be molten salt.

The fundamental idea of the invention consists in replacing the central main pump for pumping fluid through the loops of the solar array or arrays with one main pump per loop, respectively. It is consequently possible to use fewer specific pumps, and hence cheaper ones, to pump the heat-transfer fluid through the individual loops.

A single line main pump is provided per loop. Further pumps per loop are preferably additionally present. In a particular embodiment, the heat-transfer fluid transport line is therefore connected to at least one line auxiliary pump to assist the pumping of the heat-transfer fluid through the heat-transfer fluid transport line and/or the further heat-transfer fluid transport line is connected to at least one further line auxiliary pump to assist the pumping of the further heat-transfer fluid through the further heat-transfer fluid transport line.

In a particular embodiment, at least one of the pumps has a control device for controlling a volume flow rate of the respective heat-transfer fluid through the respective heat-transfer fluid transport line. The controlling is, for example, temperature-controlled.

All of the pumps used (main and auxiliary pumps) are, however, preferably fitted with such control devices. The transported quantities of heat-transfer fluid can thus be metered accurately into the individual loops. It is thus conceivable that each of the pumps is associated with its own control device, respectively. It is, however, also possible that two or more pumps are activated and/or controlled by a control device. According to a further embodiment, at least two of the pumps have a common control device for controlling a volume flow rate of the respective heat-transfer fluid through the respective heat-transfer fluid transport line.

With regard to the generation of electricity, it is advantageous to provide a larger number of solar arrays. An arrangement of a plurality of the described solar arrays is therefore also provided.

The described solar array or the described arrangement is used in a solar power plant for converting solar energy into electricity.

In summary, the following advantages are connected with the invention:

-   -   It is possible to dispense with an expensive central main pump         by using one main pump per loop in each case.     -   Cheaper control valves for controlling the flow rate of the         heat-transfer fluid through the loops can be employed, in         particular by using controllable pumps.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of a solar array in accordance with an embodiment of the present invention.

FIG. 2 shows a solar array as known from the prior art.

DETAILED DESCRIPTION

A solar array 1 in the form of a parabolic-trough solar array is shown schematically. The parabolic-trough solar array has a heat-transfer fluid transport line 11 for transporting a heat-transfer fluid, and at least one further heat-transfer fluid transport line 12 for transporting a further heat-transfer fluid.

Each of the heat-transfer fluid transport lines 11 and 12 is connected in each case to at least one solar energy collector unit in the form of parabolic-trough mirrors 113 and 123 for feeding solar energy into the heat-transfer fluid arranged in the respective heat-transfer fluid transport line 11 and 12. In the example described, the heat-transfer fluid transport lines, in this case parabolic-trough loops, are partially arranged in the focus lines of the respective parabolic-trough mirror.

The heat-transfer fluid transport line 11 and the further heat-transfer fluid transport line 12 together form a combined heat-transfer fluid transport line 10. The heat-transfer fluid and the further heat-transfer fluid are identical. In this embodiment it is a thermal oil.

The heat-transfer fluid transport line 11 is connected to a line main pump 111 for pumping the heat-transfer fluid through the heat-transfer fluid transport line 11. The further heat-transfer fluid transport line 12 is connected to a further line main pump 121 for pumping the further heat-transfer fluid through the further heat-transfer fluid transport line 12.

One control valve 112 and 122 is provided in each case per parabolic-trough loop. A safety valve 116 and 126, respectively, is in each case additionally present. In addition, control valves 114 and 124 are provided upstream from the main pumps 111 and 121 and on/off valves 115 and 125 downstream from the main pumps 111 and 121.

In contrast to the described example, FIG. 2 shows schematically a solar array with a central main pump 20. Control valves 114 and 124 are present in the heat-transfer fluid transport lines in order to be able to individually adjust the flow rate in the individual solar arrays or in the individual heat-transfer fluid transport lines.

The described parabolic-trough solar array may be employed in a solar power plant based on concentrated solar power (CSP) technology for converting solar energy into electricity.

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof 

1. A solar array, comprising: a heat-transfer fluid transport line configured to transport a heat-transfer fluid, and at least one further heat-transfer fluid transport line configured to transport a further heat-transfer fluid, wherein the heat-transfer fluid transport line and the further heat-transfer fluid transport line are coupled together to form a combined heat-transfer fluid transport line, the heat-transfer fluid transport line is connected to at least one line main pump for pumping the heat-transfer fluid through the heat-transfer fluid transport line, and the further heat-transfer fluid transport line is connected to at least one further line main pump for pumping the further heat-transfer fluid through the further heat-transfer fluid transport line.
 2. The solar array as claimed in claim 1, wherein each of the heat-transfer fluid transport lines is connected in each case to at least one solar energy collector unit for feeding solar energy into the heat-transfer fluid arranged in the respective heat-transfer fluid transport line.
 3. The solar array as claimed in claim 2, wherein the solar energy collector unit has at least one parabolic-trough mirror.
 4. The solar array as claimed in claim 1, wherein the heat-transfer fluid transport line is connected to at least one line auxiliary pump arranged to assist the pumping of the heat-transfer fluid through the heat-transfer fluid transport line and/or the further heat-transfer fluid transport line is connected to at least one further line auxiliary pump arranged to assist the pumping of the further heat-transfer fluid through the further heat-transfer fluid transport line.
 5. The solar array as claimed in claim 1, wherein at least one of the pumps has a control device for controlling a volume flow rate of the respective heat-transfer fluid through the respective heat-transfer fluid transport line.
 6. The solar array as claimed in claim 1, wherein at least two of the pumps have a common control device for controlling a volume flow rate of the respective heat-transfer fluid through the respective heat-transfer fluid transport line.
 7. An arrangement of a plurality of solar arrays, each solar array comprising: a heat-transfer fluid transport line configured to transport a heat-transfer fluid, and at least one further heat-transfer fluid transport line configured to transport a further heat-transfer fluid, wherein the heat-transfer fluid transport line and the further heat-transfer fluid transport line are coupled together to form a combined heat-transfer fluid transport line, the heat-transfer fluid transport line is connected to at least one line main pump for pumping the heat-transfer fluid through the heat-transfer fluid transport line, and the further heat-transfer fluid transport line is connected to at least one further line main pump for pumping the further heat-transfer fluid through the further heat-transfer fluid transport line.
 8. A method of use of at least one solar array for converting solar energy into electricity, the at least one solar array including a heat-transfer fluid transport line configured to transport a heat-transfer fluid and at least one further heat-transfer fluid transport line configured to transport a further heat-transfer fluid, wherein the heat-transfer fluid transport line and the further heat-transfer fluid transport line are coupled together to form a combined heat-transfer fluid transport line, the heat-transfer fluid transport line is connected to at least one line main pump for pumping the heat-transfer fluid through the heat-transfer fluid transport line, and the further heat-transfer fluid transport line is connected to at least one further line main pump for pumping the further heat-transfer fluid through the further heat-transfer fluid transport line, comprising the steps of: pumping the heat-transfer fluid and the further heat-transfer fluid though their respective heat-transfer transport lines by operation of the respective main pumps; transferring solar energy from a solar collector of each transport line arranged to the respective heat-transfer fluids being pumped through the respective heat-transfer lines; and controlling a volume flow rate of each of the respective heat-transfer fluids in the respective heat-transfer lines in accordance with predetermined temperature control criteria using at least one of control valves arranged to control flow in the heat-transfer lines and speed control of the respective main pumps.
 9. The method of use of at least one solar array as claimed in claim 8, wherein the at least one solar array is incorporated in a solar power plant for converting solar energy into electricity, further comprising the steps of: transferring the solar energy received by the respective heat-transfer fluids to an energy transfer apparatus; and generating electricity from the energy received by the energy transfer apparatus. 